This invention relates to an improved counterweight for a sealed compressor wherein the counterweight is relatively thin, allowing the entire sealed compressor housing to be made shorter.
Sealed compressors are utilized in many refrigerant compression applications. In such applications, a housing seals a compressor pump unit and a motor for driving the pump unit. Typically, the motor is maintained in a chamber which is at a suction pressure such that the motor is cooled. A shaft is driven by the motor to drive at least one element of the compressor pump unit.
In one very popular type of modern compressor, the pump unit consists of two relatively orbiting scroll members. In this type of compressor, known as a scroll compressor, first and second scroll members each have a base and a generally spiral wrap extending from the base. The spiral wraps interfit to define compression chambers. The shaft drives one of the scroll compressors to orbit relative to the other. As the two scroll members orbit, the size of the compression chambers is decreased to compress an entrapped refrigerant.
Historically, the counterweight has been contained within the geometry of the upper motor windings, and sandwiched between the crankcase and the motor stator.
A scroll compressor requires a counterweight be mounted onto the shaft. Historically, counterweights have been relatively large parts which extend for a relatively great area and axial length. It is important that a portion of the counterweight, and in particular its center of gravity, be positioned upwardly near to the orbiting scroll. This has resulted in an undesirable amount of space being required for the counterweight.